1954 Bowman #66 Robert Hantla. The two peach dots appear on every card, but the green splotch and multiple small green dots on his shoulder is rare.

1954 Bowman #60 Charley Trippi is normally seen without the green splotch on his sock, but this is recurring. Not as easy as the correct card, but not super tough.

1954 Bowman #6 Joe Perry. Most copies have the black blob on the right side across from his ear, but some do not.

1955 Bowman #62 George Blanda. Blanda comes with or without this big reddish purplish slash in the bottom right. Both are very common, I suspect this may have been a constant defect on one Blanda's sheet placements rather than something that happened during only part of production.

1955 Bowman #68 Ben Agajanian. The yellow block in upper right is frequently recurring, correct copy is easy too.

1951 Bowman 126 Dick Wildung, 135 Jack Linninger, and 144 Bill Dudley can come with this blue line. That it stops half way up Wildung could indicate it isn't a cutting line, but sure is placed exactly where the cut would be centered.

The Linninger additionally comes with a variant with a broken blue line extending deep into the border.

Also occurs on 117 Wozniak, but the line doesn't run the full length of the card. Wozniak was above Wildung, and it is possible he was also below Dudley.

EDIT: Also note the 'blue apostrophe' in upper left border.

Bought a lot of ~450 1974 Topps for a nickel a pop and found this one in it. Checking online it is recurring, with the border break in the right side being less common than the correct card but not too difficult. 1974 Topps #268 Randy Beisler

And 1974 Topps #89 Riley Odoms, with a cut line at top. This only occurs on some cards; even those cut with a slightly larger top that 'should' show the line if it was on every sheet do not always have it. Presumably this occurs on other cards in that sheet row.

Odoms is the first card on the row and Elmo Wright is to his right, the line barely goes into Wright and then stops. I don't think it is a cutting suggestion line, those lines were prevalent on Topps sheets in the 60's-70's when they would fuse together two different sections of rows on a sheet. The line can also be found on the bottom of 1974 OJ Simpson Record Breaker and the Dolphin to his right.

Thank you. The 4th card Dolphin is #365 Manny Fernandez, looks like I got 3 more to go get. Why does it have to be OJ though...

It's definitely not to guide the physical cutting of the individual sheet, I don't know the word to use describe a 'cut and paste' line marker.

1948 Leaf #2 Steve Suhey. First I've seen with this white defect on the right side; not the normal offset ink layer you see on Leafs all the time.

1994 Fleer Hardy Nickerson #456.

This big black blotch thing on the right is recurring, though very rare I think. Not that anyone cares about 1994 Fleer but I thought this was one of the nicer photo-centric mid-90's designs

1952 Bowman Small #19 George Connor. Note the border frame gaps at top and bottom, and also in the borders of the name flag banner. I don't know if this can occur on the large as well.

Recurring red line at top. Looks like it probably extends to the cards to both the left and right of Mercer on the sheet, but I don't know the sheet layout and haven't gotten around to gathering miscut scans to try and piece it together. Probably a good clue here to the layout.

1964 Topps #145 Mike Mercer

1961 Fleer #57 Bob Pellegrini 'green ear square', recurring on a minority of cards.

The cut line proceeds to 1970 Topps #27 Roland Lakes and #96 Rockne Freitas.

It may end there. I looked at a ton of #67 Sam Brunelli, who is next in this row on the sheet, but have not seen one showing a red line. This cut/splice line was not on all sheets though, so I may just not have found one. Not how the line starts to thin out as it progresses through Freitas

1962 Topps #28 Jimmy Brown. Jimmy comes with this green splotch on his neck. It is unfortunately recurring, but I think pretty difficult to find. I didn't look too hard but I missed buying the first one I noticed quite a while back and finally saw another one here that I did pick up.

A 1968 Topps #151 Tommy Nobis with the red dash variant, and a big red issue, all over his shoulder, and over the rights side of his face and his chin. Not sure if recurring yet, pretty much any Topps card can eventually be found with some kind of red or yellow ink 'explosion'.

1951 Bowman Crazy Legs Hirsch with the back blue ink doublestruck, but not the red

1965 Topps Bob Schmidt #20. Unlike most Topps cards with these cut/splice/whatever lines, this one has it on front and back.

1948 Leaf #78 Clarence Self, with sheet marks in the top left is recurring.

1964 Topps #170 Don Rodgers. The blue dot in bottom border on off center cards is recurring.

Exhibits Charley Conerly comes with or without the big slash between his helmet and his hand. Both are common

Somewhere around 50% of 1956 Topps #96 Buddy Young cards have a yellow bottom right corner, like this one.

I also found and bought this copy, with yellow splotching on the bottom left. Not sure if a recurring defect to note or just a random one off. Pretty much any old Topps card can be found with yellow-ink splotching if one looks at enough copies.

Young was only 5'4 and is one of the shortest pro football players. He set some track records before his NFL career, and was a college ball star even as a Freshman. He was the first Colt to have his number retired. With the small set sizes in the 50's, most 'common cards' were actually really good players.

Here is one of mine from the same year. AKA Hunter

1962 Topps Missing Yellow ink?
 

I've seen a few of these 'Blue Box/White Letters' Ernie Davis RCs. A couple are on eBay right now. Looks like a print defect - missing yellow ink? I tried looking for other Green Box/Yellow letter players but couldn't find any examples.

Looks like extended sunlight exposure to me.

That was my first thought. I have seen probably 4-5 of these. There is a PSA 8 on eBay right now. Just odd to see that many with the same 'exposure' or same level of damage. I'll hope to find another player someday....

1962t
 

Looking at COMC - found these blue/green examples. Partials only, however.
One is a 50/50 that looks like damage (sun or water?). The other is just the upper right corner of the green box. Weird?

1974 Topps #451 Ken Stabler comes with sheet text on the right side.

1975 Topps #120 Len Dawson. The red/yellow line at top is pretty common. The red spot above the top black border is recurring independent of the red/yellow line on cards off center to the top as well.